Identifying a CPU or I/O intensive Job.

DB2 Guy · New User Joined: 28 Oct 2008 Posts: 98 Location: Cubicle

Hi,

Apart from asking the Support (who happened to be idiots in my case) - is there any way using which I can find if some job is CPU or I/O intensive.

And if you've a list of Jobs, and the question remains same - is there any way using which I can find if some job is CPU or I/O intensive.

Provided I don't have access to SMF records...

Robert Sample · Posted: Mon Feb 27, 2012 9:21 pm

Your best bet is for the site to have Strobe or another run-time analyzer installed as they can tell you exactly.

Your next best bet is for the site to have a system monitor (Omegamon, Mainview, etc) installed. These can be used to identify which address spaces (jobs) are using high level of resources (CPU or I/O channel) and hence give clues.

AFAIK, there is no way from mere inspection to determine which the job is, since being I/O- or CPU-bound can vary depending upon the mix of jobs running in the system, the relative priority of the jobs, the Workload Manager policy in effect, and so forth. A job that is I/O-bound at 3 AM may well be CPU-bound at 3 PM.

Bill Woodger · Posted: Mon Feb 27, 2012 10:56 pm

You could look at the ratio between CPU and I/O per JOB.

You could also look at jobs in groups of "Big", "Medium" and "Small" (starting with the Big and likely not getting to the Small) and do some estimates of CPU per input, I/O per input.

These are very broad things. Really just looking at things, with a bit of a hint as to what to look at first.

Maybe doesn't work these days, but used to ask OPS which jobs they didn't like running. They generally knew which ones made the lights go dim or stopped the tape drives for other jobs. There was also someone usually in Operations Control monitoring plain "excesses" - highest CPU jobs, highest I/O jobs, longest elapsed. Then you'd get a visit :-)

PeterHolland · Posted: Mon Feb 27, 2012 11:03 pm

DB2 Guy · New User Joined: 28 Oct 2008 Posts: 98 Location: Cubicle

Thank you Robert. that's what I told my lead but they insist...

DB2 Guy · New User Joined: 28 Oct 2008 Posts: 98 Location: Cubicle

Thanks Bill - that's what I'm doing but that's a not something give me a good so, but yeah, I'll move slowly.

Peter - when I asked them if they can provide me with SMF Record Type 70 Subtype 1 report, if they generate it - the question was, what is SMF? When told what is SMF, answer was - yes, we generate something of that sort but not sure if it's for this record or not!

PeterHolland · Posted: Tue Feb 28, 2012 10:46 pm

Well, DB2Guy what can i say. There are different support groups like application support, system support. Maybe you talked to the wrong people. If not then i have to apologize.